Sökning: "21cm line"

Hittade 5 avhandlingar innehållade orden 21cm line.

  1. 1. Neutral gas properties of high-redshift analog galaxies : 21cm observations of Lyα and LyC-emitting galaxies

    Författare :Alexandra Le Reste; Matthew J. Hayes; John Cannon; Rychard Bouwens; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Galaxies; Lyman alpha; Lyman Continuum; 21cm line; Interacting galaxies; Epoch of Reionization; Astronomy; astronomi;

    Sammanfattning : Neutral hydrogen (HI) is the most abundant baryonic element and a crucial component of galaxies. In the early universe, the interaction between neutral gas and the light produced by galaxies is thought to have given rise to cosmological reionization. LÄS MER

  3. 2. Simulations of Cosmic Reionization : Shapes & Sizes of H II regions around Galaxies and Quasars

    Författare :Martina M. Friedrich; Garrelt Mellema; Jonathan Pritchard; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; astronomi;

    Sammanfattning : After the era of recombination, roughly 360 000 years after the big bang (redshift 1100), the universe was neutral, continued to expand and eventually the first gravitationally collapsed structures capable of forming stars, formed. Observations show that approximately 1 billion years later (redshift 6), the Universe had become highly ionized. LÄS MER

  4. 3. Multi frequency interferometer studies of active and starburst galaxies

    Författare :Evert Olsson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; galaxies: active; galaxies: ISM; galaxies: starburst; galaxies: evolution;

    Sammanfattning : We report the results of a multi-frequency study of three interactinggalaxies: NGC 5218, NGC 1614 and NGC 4194 (the Medusa merger). These sourcesbelong to different classes of active and starburst galaxies. LÄS MER

  5. 4. How ISM properties drive Lyman Continuum Escape

    Författare :Johannes Puschnig; Matthew Hayes; Göran Östlin; Rahman Amanullah; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astrophysics; Cosmology; Extragalactics; Reionization; Lyman Continuum; Interstellar Medium; ISM; Tololo 1247-232; Astronomy; astronomi;

    Sammanfattning : The thesis introduces physical processes that are at work in astrophysical plasmas and reviews the current state of research related to the emission of ionizing photons, i.e. Lyman continuum (LyC). Star forming galaxies and active galactic nuclei are discussed as sources of LyC. LÄS MER

  7. 5. Molecular gas and ionizing radiation in star-forming galaxies

    Författare :Johannes Puschnig; Matthew Hayes; Göran Östlin; Amélie Saintonge; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; astrophysics; galaxies; star formation; starburst; interstellar medium; Lyman continuum; Lyman alpha; reionization; gravitational instability; molecular gas; clump formation; Astronomy; astronomi;

    Sammanfattning : In cosmic history, some of the major changes such as reionization were driven by baryons (i.e. the stars and gas in galaxies), despite the fact that they contribute only few percent to the total mass-energy budget in the Universe. LÄS MER